1. Field of the Invention
The present invention relates to brazing and/or soldering materials for making connections by brazing or soldering, and a method for manufacturing such materials.
2. Description of the Related Art
Soldering is a method of connecting two base materials (or base metals) by thermally melting an alloy or metal with a melting point lower than that of the base materials so that the molten alloy or metal fills gaps between the base materials. The base materials themselves are not melted. Soldering is widely used in electronics because of its ability to connect complex, precision parts as well as metals of different types while having little effect on the base materials. Hard solder (also known as high melting solder) has a relatively high melting point and includes soldering materials such as silver, gold, as well as other types of hard solder. In contrast, soft solder (also known as low melting solder) has a relatively low melting point.
Soft solder, which is commonly referred to simply as solder, usually comprises tin and/or lead, and is widely used for lead frame connections in electronic products where a conductive connection is required. Conductivity is usually more important to solder than mechanical strength, and high wettability of the base materials is required. The presence of an oxidation coating on the joining surfaces of the base metals is known to greatly affect the wettability of solder and hard solder (brazing alloy below) used in brazing and soldering.
Flux has conventionally been used during normal soldering and brazing to remove any oxidation coating from the surfaces of the base metals. A problem common to soldering and brazing techniques that use flux for connecting leads in electronic products, even when a non-corrosive flux is used, is contamination of peripheral components and materials when the flux is applied. In addition, while there are cases in which flux containing a halogen is used for soldering, cleaning to remove any residual flux is generally required after soldering. Furthermore, while there are also cases in which residual flux is not cleaned after soldering, these methods either use a flux with a low halogen content, and thus sacrifice wettability, or use a flux with a high halogen content to assure solder wettability and thus risk the danger of migration resulting from the halogen component in the residual flux.